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Message loop work hangs in wxPython / Qt examples on Mac. Fixed in examples. Needs further debugging in next releases. #442
Description
These examples freeze during initial loading or later when typing something on a page. Issues occurs in v66.0 on Mac 10.9.
Temporary solution
See Migration Guide doc "v66+ Changes to Mac apps that integrate into existing message loop (Qt, wxPython)":
https://github.com/cztomczak/cefpython/blob/master/docs/Migration-guide.md#v66-changes-to-mac-apps-that-integrate-into-existing-message-loop-qt-wxpython
Reported problem on the CEF Forum in many details:
https://magpcss.org/ceforum/viewtopic.php?f=6&t=16181
I can see ERROR:gpu_process_transport_factory.cc(1017)] Lost UI shared context error message in console, however this message doesn't seem to be the cause, as I also see this message when running hello_world.py example and it works fine.
The Lost UI shared context error can be safely ignored according to:
https://stackoverflow.com/questions/49094399/chromedriver-showing-lost-ui-shared-context
hello_world.py, screenshot.py and tutorial.py examples do work fine on Mac.
I can also see ERROR:command_buffer_proxy_impl.cc(133)] ContextResult::kTransientFailure: Failed to send GpuChannelMsg_CreateCommandBuffer.
Passing disable-gpu and disable-gpu-compositing switches to cef.Initialize does not help. However it seems that the ContextResult::kTransientFailure.. error message disappears after these switches are passed (though more testing needed if it's just luck).
Issue is not related to recent Cython dupate, as I've tested both 0.25.2 and 0.28.4 and the issue occurs in both.
TODO: Compare cefpython/src/subprocess/main_message_loop* files with cef/tests/shared/browser/main_message_loop* files. These files may have been changed after v66 update.
Activity
[-]qt.py PySide and wxpython.py examples freeze randomly on Mac[/-][+]Message loop hangs in wxPython / Qt examples on Mac[/+][-]Message loop hangs in wxPython / Qt examples on Mac[/-][+]Message loop work hangs in wxPython / Qt examples on Mac[/+]Fix qt.py and wxpython.py examples on Mac (#442).
cztomczak commentedon Aug 7, 2018
Examples qt.py and wxpython.py fixed in rev b20c79b by enabling external message pump. This is just a temporary solution that combines two different approaches of integrating message loop at the same time: 1. Do message loop work in a timer 2. Enable external message pump. A correct approach is to do only one of these and not both at the same time.
[-]Message loop work hangs in wxPython / Qt examples on Mac[/-][+]Message loop work hangs in wxPython / Qt examples on Mac. Temporary solution: enable external message pump and also run message loop work in a timer.[/+][-]Message loop work hangs in wxPython / Qt examples on Mac. Temporary solution: enable external message pump and also run message loop work in a timer.[/-][+]Message loop work hangs in wxPython / Qt examples on Mac. Temporary fix: enable external message pump and also run message loop work in a timer.[/+]Update Migration Guide document. Changes to Mac apps that
cztomczak commentedon Aug 7, 2018
Migration Guide document was updated.
cztomczak commentedon Aug 7, 2018
Further debugging of the issue:
https://github.com/chromiumembedded/cef/search?q=cefappprotocol&unscoped_q=cefappprotocol
https://bitbucket.org/chromiumembedded/java-cef/src/master/native/util_mac.mm?fileviewer=file-view-default
it might be that this wasn't implemented properly.
Mouse context menu and <select> control crash app on Mac #156 (comment)
https://github.com/cztomczak/cefpython/blob/master/src/client_handler/util_mac.mm#L18
cefpython/src/cefpython.pyx
Line 502 in 4e77c93
Further changes to message loop issues on Mac (#442).
[-]Message loop work hangs in wxPython / Qt examples on Mac. Temporary fix: enable external message pump and also run message loop work in a timer.[/-][+]Message loop work hangs in wxPython / Qt examples on Mac[/+][-]Message loop work hangs in wxPython / Qt examples on Mac[/-][+]Message loop work hangs in wxPython / Qt examples on Mac. Fixed in examples. Needs further debugging in next releases.[/+]cztomczak commentedon Aug 16, 2018
Fixes to CefAppProtocol did not change anything. Need to debug this further in v68+ release and on Mac 10.10.
cztomczak commentedon Sep 6, 2018
Fixes to external message pump in upstream CEF:
https://bitbucket.org/chromiumembedded/cef/commits/869efa1
cztomczak commentedon Sep 28, 2018
Maybe related:
https://bitbucket.org/chromiumembedded/cef/issues/2495/mac-cefclient-external-message-pump-crash
cztomczak commentedon Dec 18, 2019
Maybe related issue reported on CEF Forum:
https://magpcss.org/ceforum/viewtopic.php?f=6&t=17118
cztomczak commentedon Aug 24, 2020
It seems the issue on Mac was that Chromium was messing with NSTimer, so that all wxTimers stop working. See for more details https://www.magpcss.org/ceforum/viewtopic.php?f=6&t=17118 .